Conventional pen instruments were simply designed for writing. However, with the diversification of commercial products and different demands from different users, manufacturers of pens have developed diversified pens with different shapes and functions. For example, there are pens with different patterns, textures, or attached ornaments. There are even pens with light or sound emitting elements to emit light or sound.
In view that different patterns, textures, or ornaments on pens only provide visual changes in pens, and pens with light or sound emitting elements must be battery-powered to actuate electronic components of the light or sound emitting elements, it is desirable to develop a pen instrument that has integrated functions to serve as a writing instrument, an ornament, and a sound-producer.